Quiz: Howstuffworks

Scientific Facts That Aren’t Actually True

Bambi Turner

Image: krisanapong detraphiphat / Moment / Getty Images

About This Quiz

In 1998, a British doctor published a groundbreaking study linking vaccines and autism. Terrified parents quickly took note, questioning their children's pediatricians or even skipping vaccines altogether. Just two decades later, this reluctance to vaccinate has negated years of vaccination progress and caused nearly eradicated illnesses like measles or whooping cough to threaten the lives of a whole new generation of children. But here's the kicker -- no one has been able to replicate the results of the study. The doctor who published the initial study has lost his license to practice medicine and the medical journal that published his work has issued a retraction -- but that hasn't stopped the fact that many people still accept his initial work as fact.

And that's just one example of this phenomenon. Despite the fact that science and medicine are continuously reaching new heights, far too many people cling to folk remedies, old wives' tales, disproved facts and plain old bad science. It's why turkey "makes you so sleepy," a goldfish "has no memory," and a penny dropped from the Empire State Building is "deadlier than a speeding bullet." Think you can know the truth about some of the most commonly repeated scientific "facts?" Prove it with this quiz!

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What color is blood when it's still inside your veins?

Red

Blue

It depends on blood type.

It depends on skin tone.

Running through your veins, pumping into your heart or oozing from a wound, blood is always the same color -- red. Well, unless you happen to be an octopus or a horseshoe crab. Both of these critters are among the rare species running around with blue blood.

What happens if you cut an earthworm in half?

You'll have two thriving worms.

You'll have two dead worms.

You might end up with one living worm.

Several smaller worms will pour out from inside.

No, cutting an earthworm in half will not result in two thriving worms. While some flatworms can regenerate when cut in half, earthworms cannot. The best case scenario is that the head end of the cut earthworm will survive, but the tail end is a goner.

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When do hair and fingernails stop growing?

Pretty much when you die

Never

1 year after death

5 years after death

Ever heard that fingernails and hair continue to grow after you die? Creepy, but not true. When you die, body processes stop -- including nail and hair growth. This rumor likely reflects the fact that dehydration after death causes skin to shrink, which can make hair and nails appear to have grown.

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Which of these has been scientifically proven to help cure a cold the fastest?

Chicken soup

Orange juice

Rest

Antibiotics

No, antibiotics won't cure a cold. They are designed to attack bacteria, but a cold is caused by a virus, so antibiotics will have zero effect. Orange juice and soup can't really hurt, but also won't help. Want to get that cold out of your system more quickly? Get plenty of rest and relaxation to speed healing.

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Which of these is true regarding water and electricity?

Pure water is an insulator.

Water in any form conducts electricity.

Hanging out in the ocean protects you from lightning.

Water can never conduct electricity.

Contrary to rumor, pure water -- such as distilled -- is actually an insulator, not a conductor. When you are warned to steer clear of water during a lighning storm, it's because all of the minerals in the water are excellent conductors. The threat doesn't come from the water itself.

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Did humans ever have to worry about being eaten by dinosaurs?

Yes, but only small ones.

Yes, but only for around 50,000 years.

Yes, unless the human could run fast.

Nope.

The closest any human has ever came to a dinosaur was when you saw that T. rex skeleton at the museum. Dinosaurs died out around 65 million years before humans came into the picture, so the two species never cohabited.

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Why are you so darn sleepy after chowing down on a big Thanksgiving dinner?

You just ate a huge meal.

Tryptophan in turkey

It's late in the day.

Enzymes in the gravy

The enzyme tryptophan is involved in sleep, but no one eats enough turkey on Thanksgiving to ingest any meaningful amount of this amino acid. Instead, that after-dinner crash comes because your body is so busy digesting all that food, leaving you little energy for other activities.

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What exactly causes embarrassing acne?

Chocolate

Overactive glands

Fatty foods

Fast food

It's safe to finish that candy bar -- chocolate does not cause acne like you might have heard. Instead, pimples come from overactive sebaceous glands, but scientists aren't exactly sure what gets these glands so worked up.

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What happens if you eat ice cream to soothe a painful sore throat when you have a cold?

So much mucus

Increase in fever

Cooling effect on throat

Prolong your illness

The old wives tale that dairy consumption increases mucus production has caused many people to steer clear of ice cream or milk when nursing a cold. Today, scientists know that there's no connection between dairy and mucus, so it's safe to enjoy that ice cream when your throat is too sore for anything else.

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What's the worst thing that can happen if you crack your knuckles all the time?

Annoy friends and family

Arthritis

Broken digits

Paralyzation

Contrary to rumor, cracking your knuckles does not contribute to arthritis or any other long-term health effects. Dr. Donald Unger proved this when he spent 50 years only cracking the knuckles in one hand, but not in the other. After half a century, he had no difference in physical health between the two hands.

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What determines the direction that liquid will take when it affects the drains in your home?

Coriolis effect

Which hemisphere you live in

How the fixtures were installed

How hard you flush

Sorry Simpsons; the Coriolis Effect does determine wind patterns, but has no effect on the way water flows out of your toilet when you flush. Toilets in both hemispheres can drain clockwise or counterclockwise depending on the fixtures and how they were installed.

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How much of the brain is the average human using on a given day?

10 percent

About a third

Almost half

Pretty much all of it

No, humans don't limit themselves to using 10 percent of their brains, leaving the rest of that gray matter to rot. In fact, the brain uses around 20 percent of all the energy used by the body, which means you're using pretty much every part of your brain at almost all times.

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What happens when kids consume sugar?

Hyper activity

Bad behavior

Poor listening skills

They enjoy a sweet treat.

A 1994 double-blind, peer-reviewed study found that sugar does not make kids hyper or lead to bad behavior. What it does is impact the way parents think; parents told their kids are given sugar rate the child as more hyper than parents who are told the child was given no sugar -- even if neither group had any sweets.

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Which of these are vaccines scientifically proven to cause?

Adults

Autism

Depression

Weight gain

Every major medical institution on the planet recommends basic vaccines to prevent illness and allow people to live healthy lives. That MMR/Autism study by Andrew Wakefield that spurred the whole anti-vaxxer movement? It was based on a sample size of 12 and rife with fraud. Wakefield lost his license to practice medicine and no other study has ever come close to replicating his results.

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How long does swallowed gum hang around in your stomach?

7 years

About a year

3 months

A few hours to a few days

Humans have been chewing on gum for fun since the first version of the product -- made from spruce resin -- came out in the 1840s. Rest assured that swallowed gum doesn't linger for 7 years; it's processed just like other food and sent out with other waste products.

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Astronaut Neil Armstrong was asked about the Great Wall of China shortly after his trip to the moon. What was his response?

Couldn't see it

It was the only thing I could see.

I saw some parts of it.

I only saw the parts with lights.

In perfect conditions, flying at 100 miles above the Earth, it's sometimes possible to see portions of the Great Wall of China. Far from being the only manmade object visible from outer space, however, Neil Armstrong himself specifically said he couldn't see it at all -- and could only distinguish the continents and water bodies.

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How long is a goldfish's memory?

3 seconds

About a minute

Around a day

Several months or more

Forget everything you've heard about goldfish and their sad, three-second memories. Even wild goldfish can be trained to remember things -- and some of those memories can endure three months or more.

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What would happen if a penny dropped off the Empire State Building hit you on the head?

You would die.

You'd be hospitalized.

You might be annoyed.

There's no gravity that high up.

A penny dropped from the top of the Empire State Building wouldn't kill anyone. Instead, its flatness would slow it enough that it would only be traveling at around 25 mph when it reached the ground. That might be annoying if it hit you, but it certainly wouldn't cause any real injury.

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Does an apple a day keep the doctor away?

Nope

No, but two apples a day does.

Only if it's a Granny Smith

Only if it's an Apple watch

It's great marketing for apple sellers, but there is no scientific link between eating an apple each day and time spent at the doctor. For real -- it's actually been studied. A 2015 study published in "JAMA Internal Medicine" found that apple eaters visit the doctor about as much as non-indulgers.

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Why does that ostrich have her head hidden in the sand?

She's scared.

She's stupid.

She's checking on her eggs.

Ostriches never do that.

Forget the rumors; ostriches don't stick their heads in the sand because they are scared or shy. They do bury their eggs underground, so mom might duck her head down at times to take a peek -- which might make it appear she's gone into hiding for a minute.

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When did most educated people understand that the world was a sphere?

2000 years ago

When Columbus reached America

Around the 1700s

Within the past century

No, people did not think Columbus was going to sail off the edge of the Earth in 1492. Most educated people have understood that the Earth is round since the ancient Greeks figured it out starting around 350 BC.

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Which of these gives you a cold?

Going out without a jacket

Cold weather

Going out with wet hair

Viruses

Forget the old wives' tales; you don't get a cold because it's cold outside, or you went out with a wet head or forgot your jacket -- colds come from viruses, period. If it seems like you get more colds in the winter, it's probably because you're spending more time indoors sharing close quarters with other people, who are sharing their germs with you.

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What happens to your eyes if you sit too close to the TV?

Maybe short-term eyestrain

Nearsightedness

Farsightedness

Permanent damage

No matter what your mother may have told you, sitting too close to the TV does not permanently damage eyes. The worst it can do is cause temporary eye strain, which resolves itself with a bit of R&R.

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How many human years is the first year of a dog's life equivalent to?

1 year

3 years

7 years

15 years

According to the American Kennel Club, the first year of a dog's life is equivalent to about 15 human years. Year 2 for a dog is another 9 human years, and every year after that is about 5 human years.

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Which of these is true about gravity in space?

There's no gravity at all in space.

Some gravity fields in space are super strong.

Gravity is really weak outside Earth.

Earth has the strongest gravity in the universe.

When you exit the Earth's gravitational field, it can seem like gravity in space is really weak, but in fact, outer space gravity is super strong. It's what keeps all the planets where they are, slinging them around an orbit to circle the sun.

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Which of these is true about the moon?

The same side is always in total darkness.

Only one side is visible from Earth.

There's no light on the moon.

You can't see Earth from the moon.

The whole "dark side of the moon" thing isn't really true. Sure, we can only see one side of the moon from Earth, but both "sides" of the moon spend time in the light. Each side is light for about two weeks, then dark for a few weeks, so no area of the rocky surface is ever in permanent darkness.

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Is Earth the only planet in our solar system with water?

Yes

No

No one knows

There's no water on Earth.

While Earth is the only planet with consistent supplies of liquid water, it isn't the only planet with water. Scientists know that Mars has water, which even flows at times, while moons of Saturn and Jupiter have subterranean seas.

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How long does it take for bacteria to contaminate food once you drop it on the floor?

Less than a second

5 seconds

30 seconds

It's safe to eat floor food.

Forget the 5 second rule. Bacteria starts to contaminate food the second the food hits the floor. The longer the food stays down, the more bacteria climbs on board to threaten your gastrointestinal health if you decide to pick up the food and eat it.

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How long did Galileo spend in jail for insisting that the sun, not the Earth was the center of the universe?

1 day

20 years

His entire life

He was hanged.

Italian astronomer Galileo raised eyebrows when he claimed that the sun, not the Earth, was the center of the universe. While history leads us to believe he was persecuted for his ideas, he actually only spent one day in prison. The church actually sponsored his research, and only put him on trial because he was teaching his theories as facts without proof -- not because they were heretical.

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What happens to dead brain cells?

They're gone forever.

They kill cells around them.

They can be removed via surgery.

They regenerate.

No, dead brain cells aren't gone forever. Scientists have known since the '60s that just like many other cells in the body, brain cells damaged by disease or injury can regenerate and restore themselves over time. Isn't the body amazing?

What happened to Ben Franklin when lightning struck his kite?

Lightning never struck the kite.

He died.

He suffered a stroke.

He was badly burned.

Yes, Benjamin Franklin flew a kite in a lightning storm in 1752 to experiment with electricity, but lightning never struck the kite. Instead, Franklin used a metal wire to attract ambient electrical charges in the air -- not huge, dangerous bolts of lightning,

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Which of these is true of frozen vegetables?

There's no real benefit to eating them.

They are always better than fresh veggies.

They're not as healthy as fresh veggies.

They are about equally as nutritious as fresh veggies.

On a budget but trying to get your greens? Flash-frozen veggies are about equal to fresh veggies in terms of nutritional value. If you can't afford fresh vegetables or can't find them off-season, frozen veggies can give you all the nutrients and fiber you're looking for.

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When are people in the United States closest to the sun?

In winter

In summer

In autumn

In spring

Contrary to what you might have heard, seasons on Earth are determined by the tilt of the planet's axis, not by its distance from the sun. In fact, people in the U.S. and other parts of the northern hemisphere are actually closest to the sun in the winter when temperatures are the lowest.

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How long should you wait to swim after you finish eating?

60 minutes

30 minutes

10 minutes

No waiting required

The whole idea of waiting 30 minutes after eating before you swim is an old wives' tale with no scientific basis. It's perfectly safe to swim right after chowing down, so feel free to jump in with both feet.

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How many times can lightning strike and hit a single spot?

Only once

No more than 3 times

An infinite number of times

Lighting never actually makes contact with anything.

Yes, lightning can strike the same spot more than once. In fact, a Virginia park ranger named Roy Sullivan was struck 7 times over a 30-year period, and tall buildings like the Empire State Building get struck all the time.

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What happens to a person of average health if they eat lots of carrots?

Super eyesight

Damage to eyes

Ability to see in the dark

Not much

Back in WWII, British pilots blamed carrots for their awesome eyesight, when in fact it was a little trick called radar that was allowing them to hit their targets. The rumors stuck, and carrots are still associated with good vision. For people who aren't malnourished, however, chowing down on these veggies will have little to no effect on vision.

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How do babies with pets at home fare in terms of lifetime allergies?

Fewer allergy issues

More allergy issues

It depends on the type of fur.

It depends if they sleep with the animal.

Believe it or not, babies who grow up with a pet in the house are less likely than those without pets to suffer allergies over time. This effect only works if the baby is under a year old, and getting a pet later in life has no impact on allergy occurrence.

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What is most likely to happen if you take antioxidant supplements?

Nothing

You're more likely to get cancer.

You're less likely to get cancer.

You'll lose weight.

According to the National Cancer Institute, antioxidant supplements don't prevent cancer, and if you take them when you already have cancer, you may end up with a worse outcome. Some supplements actually cause tumors to grow, rather than shrink.

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When can a flu shot give you the flu?

If you're an infant

If you're elderly

If your immune system is weak

Never

Flu shots contain a dead flu virus and absolutely, positively cannot give you the flu. Around 1 to 2 percent of people who get this shot may have mild symptoms like a fever, but that's just a sign that the immune system is responding to the vaccine and gearing the body up to fight off future flu infections.

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Which of these is scientifically proven to cause stomach ulcers?

Spicy food

Dairy

Stress

Bacteria

Since 1982, scientists have known that helicobacter pylori, a type of bacteria, causes peptic ulcers. Spicy food might aggravate an existing ulcer, but it won't cause one to form.

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